Rotary grinding and polishing tool.



E. CAVICCHI.

ROTARY GRINDING AND POLISHING TOOL. APPLICATION FILED OCT. I9, I9 7.

1,260,326 Patented Mar. 26, 1918.

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ERCOLE OAVIGCHI, O18 QUINCY, MASSACHUSETTS.

ROTARY GRINDING AND POLISHING TOOL.

Specification of Letters Patent.

Patented Mar. %6, 1918.

Application filed. October 19, 1917. Serial No. 197,503.

To all whom it may concern:

Be it known that I, ERCOLE CAv1ooHI,a citizen of the United States, and resident of Quincy, county of Norfolk, State of Massachusetts, have invented an Improvement in Rotary Grinding and Polishing.

I worn.

In the use of rotary grinding tools it is customary to supply a fluid, such as water, to facilitate the grinding operation, and in some instances also to supply a granular or pulverized abradant or polishing material to the surface being treated.

In such cases the centrifugal action of the rotary tool tends to force the fluid or mixture away from the center of the rotary tool so that the abrading surface or surfaces near the center of the tool run dry. This causes an uneven action of the tool and prevents the production of a smooth flat surface.

Another object of the invention therefore is to provide means which will force more or less of the fluid toward the center of the tool during its operation. This is accomplished in the preferred embodiment of the invention illustrated herein by providing a rotary grinding tool with a series, or preferably a plurality of concentrically arranged series of abrading blocks having their forward faces inclined backwardly in respect to radial planes extending from the axis of the tool to the forward apexes of said forward face, said apexes preferably being the lines of intersection of the forward faces with the curved, preferably concentric, outer faces of the blocks.

My invention contemplates the production of a block of the character set forth as an article of manufacture, said block preferably being provided with beveled walls adapted to fit complementary beveled walls 0" sockets in the rotary tool. Other objects and features of the invention will more fully appear from the following description and the accompanying drawings and will be pointed out in the annexed claims.

.A preferred embodiment of the invention is shown in the accompanying drawings.

In the drawings:

Figure 1 is a plan view of a rotary grinding or polishing tool embodying my invention,

Fig. 2 is an elevation of the under side of the tool illustrated in Fig. 1,

Fig. 3 is a side elevation thereof,

Fig. 4 is a detail View partly in section showing the manner in which one of the sectors or plates carrying the abrading blocks are connected to the spider through which said sectors are propelled.

Fig. 5 is an elevation of the lower side of I a modified form of polishing tool,

Fig. 6 is an inverted detail sectional view on lines 66 Fig. 5, and,

Fig. 7 is a perspective view of a preferred form of polishing block.

The polishing toolwhich forms the subject of the present application is adapted for use with any form of rotary polishing or grinding machine. It is however designed more especially for use in machines of the type disclosed in my prior Patent No. 1,126,615 granted January 26, 1915 in which a truck supports an electric motor which drives, through suitable gears, a vertical shaft the lower end of which extends into a socket in a spider to which plates carrying the abrading or grinding blocks are secured.

As illustrated in the accompanying drawings (Figs. 1 to 4) the grinding tool as a whole comprises a spider having an annular peripheral rim 1 connected by radial arms 2 with a central hub or boss 3 having an angular, preferably square socket 4 to receive the squared end of a rotating shaft. A series of sector-like plates 5, 6, 7 are secured respectively to the radial arms 2 by universal connections, said connections being disposed at substantially the central ortion of the sectors. A preferred means or thus securing the sectors to the spider comprises an upward-tapered pin or stud 8 which engages a complementary socket in the arm 2 and is held therein by a cotter pin. The lower end of said tapered stud is provided with a spherical head 9 which is seated in a suitable socket in the sector 5 and is retained therein by a strap or keeper 10 which embraces the stud above the spherical head and is provided at its ends wit slots which pass over lugs 11 extending upwardly from the plate 5, the keeper 10 being retained upon the lugs 11 b suitable cotter p1ns 12.

In the preferre form of grinding tool, the sectors are three in number and symmetrically disposed about the center of said tool. In order to revent the sector plates from rotating the orward end of each sector is provided with a recess 13, the walls of which embrace a stud 14 projecting downwardly from the under surface of the peripheral rim 1 of the spider, said rim being provided, in the skeleton constructlon shown herein, with inward extensions 15 carrying said lugs. The undue tilting of the sector plates 5 may be prevented by lugs 16 made integral with and depending from the spider at suitable points.

Each of the sector plates preferably is provided with polishing blocks 17 18 and 19, preferably three in number, which are arranged in triangular relation to one another, the block 17 bein located adjacent the periphery of the spi er, the block 18 in advance thereof and farther toward the center of the polishing tool, while the block 19 may be positioned substantially opposite the block 17 and still nearer the center of the grinding tool than the block 18.

By reason of this construction each sector is provided with a three-point bearing surface to engage the material operated upon and consequently all of the blockswill bear upon the material at all times and under all conditions. Similarly the grinding tool being provided with three sectors causes all of the sectors to force all of their grinding blocks into contact with the surface being treated all of the time.

In tools of this character a'fluid, such as water, is supplied to the surface being ground and ordinarily a granular or pulverized grinding and polishing material is distributed in the path of the tool. Insuch case the centrifugal action of the rotating tool tends to force the liquid or the mixture of granular material and liquid away from the center of the tool so that the grinders which are most near the center run dry. This causes an uneven action upon the surface being treated.

In order to avoid this defect the grinding blocks 17, 18, 19 are given a special form. In the preferred form which is illustrated herein the blocks have inner and outer curved faces 20, 21 which are concentric with the axis of the grinding tool and forward face 22 which extend backwardly from radial lanes extending fromthe axis of the grinding tool to the a exes 23 of the forward face of the blocks, t ese apexes being the line at which the forward faces 22 intersect the outer face 21.

. the abrading In the operation of the tool which is rotated in the direction indicated by the arrow, Fig. 2 the portion of the material encountered by the forward face of the abrading blocks which does not pass beneath said. face is forced inwardly into the path of the forward face of the next succeeding block which is located nearer the axis of the tool so that the fluid or mixture of abradant and fluid which is supplied to the surface being treated is consequently being forced toward the center of the tool in opposition to the action of the centrifugal force.

B reason of this construction and operatlon the central portion of the tool is supplied with fluid or a mixture of fluid and granular grinding material and does not run dry so that an even action upon the surface of the material treated is obtained.

In order to provide for the facile assembling of the abrading blocks in the tool and for their ready removal and replacement when worn the sides of the block may be tapered as illustrated in Fig. 6 or provided with one or more tapered portions 25, 26 as illustrated in Fig. 7.

When the blocks are made in this manner they may be quickly inserted into corresponding recesses in the sector plates whose weight when the machine is in operation will crowd the beveled portions firmly into their sockets.

A modified form of the invention is illustrated in Figs. 5 and 7 in which the spider comprises a plurality of rings 27, 28 concentric with the hub 29, said rings being connected by arms 30 and the inner rings to the hub 29 by arms 31. The spider thus constructed provides a circumferential series of trapezoidal-like sockets which are adapted to receive the abrading blocks. These sockets have upwardly converging walls 32-33, Fig. 7 which embrace and hold tightly the abrading members 31.

The arms 30 and 31 of the spider incline backwardly relatively to a radial plane extending from the axis of said spider to the outer ends of said arms, so that the forward face of each abrading block has a rearward inclination which tends to force the material supplied to the surface to be ground toward the center in the manner described in respect to the embodiment of the invention disclosed in Figs. 1 to 4 inclusive. The radial arms 30 and 31 preferably are so disposed that blocks which form members of the concentric series are disposed in irregular or staggered relation.

Any with abrading blocks but preferably alternate sockets are thus utilized.

It will be understood that the embodi ments of the invention disclosed herein are illustrative merely and not restrictive and that various modifications may be made within the spirit and scope of the following claims.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A grinding tool comprisin a rotatable supportlng member and a plurallty of abrading mem ers rigidly secured thereto at different distances from the axis of rotation, said members having inner and outer faces concentric with the axis of rotation and their forward faces inclined backwardly from radial planes extending from the axis of rotation to the forward apexes of said faces, whereby material lying in the path of said abrading blocks w1ll be forced toward the axis of rotation.

2. A grindin tool comprising a plurality of independent y movable sector-llke suporting plates having three abrading memhers secured thereto in triangular relation at different distances from the axis of retation, said abrading members having inner and outer faces concentric with the axes of rotation and their forward faces inclined backwardly from radial planes extending from the ,axis of rotation to the forward apexes of said faces.

3. A inding tool comprising a rotatable supportmg member having a plurality of sockets located at different distances from the am's of rotation of said supporting member abrading members secured in said sockets having their inner and outer faces concentric with the axis of rotation and their forward faces inclined 'backwardly from radial planes extendin from the axis of rotation to the intersectlon of the forward face with the outer concentric faces.

4. A grinding tool comprising a rotatable supporting member having a plurality of sockets provided with upwardly converging walls to receive and retain abrading members, abrading members in said sockets having tapered walls to fit said sockets and having their forward faces inclined backwardly from radial planes extending from the axis of rotation to the forward apexes of said abrading members.

5. An abrading member for a device of the class described comprising a block of abrading material having concentric inner and outer faces and a forward face inclined backwardly from a radial plane extending from the center of the curvature of said goncentric faces to the apex of said forward ace.

6. An abrading member for a device of the class described comprising a block of abrading material having concentric inner and outer faces and a forward face inclined backwardly from a radial plane extending from the center of the curvature of said concentric faces to the intersection of said forward face with the outer face.

In testimony whereof, I have signed my name to this specification.

ERCOLE CAVICCHI. 

